Compressor with transmission

ABSTRACT

A compressor with a transmission includes a clutch that varies the rotational speed of an output shaft between two different speeds. The clutch includes a friction layer, which secures a ring roller by movement of the ring roller in a first direction (securing direction), a first control chamber, a first control piston accommodated in the first control chamber and movable in the direction of an input shaft axis, a first thrust bearing between the first control piston and the ring roller, a second control chamber facing the first control chamber, a second control piston accommodated in the second control chamber and movable in the direction of the axis), a second thrust bearing between the second control piston and the ring roller, and a pressure control mechanism, which controls a first control pressure supplied to the first control chamber and a second control pressure supplied to the second control chamber.

BACKGROUND OF THE INVENTION

The present invention relates to a compressor with a transmission.

Japanese Laid-Open Patent Publication No. 2007-107412 discloses a conventional compressor with a transmission. The compressor with a transmission includes a housing, a compression mechanism, an input shaft, an output shaft, a transmission mechanism, and a control mechanism. The compression mechanism is provided in the housing and compresses refrigerant. The input shaft extends into the housing from the outside of the housing and is supported to be rotational about the axis. The output shaft extends in the housing and is supported to be rotational about the axis to drive the compression mechanism. The transmission mechanism is provided inside the housing between the input shaft and the output shaft. Also, the transmission mechanism drives the compression mechanism at different speeds by transmitting torque of the input shaft to the output shaft and also by selectively increasing and decreasing the rotational speed of the input shaft before transmitting to the output shaft. The control mechanism controls the transmission mechanism.

The transmission mechanism includes a first planet gear mechanism, which is located relatively frontward in the axial direction, that is, relatively close to the input shaft, and a second planet gear mechanism, which is located relatively rearward in the axial direction, that is, relatively close to the output shaft. Each of the first and second planet gear mechanisms includes a sun gear, planet gears, a carrier, which rotationally retains the planet gears, and ring gears, which respectively engage with the planet gears. A thrust bearing and a radial bearing are arranged between each ring gear and the housing. The ring gears can be fixed to or rotational with respect to the housing.

The control mechanism includes a first one-way clutch, which is located between the ring gear of the first planet gear mechanism and the housing, a first clutch, which is located between the ring gear of the first planet gear mechanism and the carrier, a second one-way clutch, which is located between the ring gear of the second planet gear mechanism and the carrier, and a second clutch, which is located between the ring gear of the second planet gear mechanism and the housing. The first and second clutches each secure the corresponding ring gear to the carrier or the housing by being displaced in the forward or rearward direction.

According to the conventional compressor configured as described above, the first and second clutches independently or simultaneously secure or release the ring gears. Then, the first and second one-way clutches permit or restrict relative rotation of the ring gears with respect to the housing or the carrier. Thus, transmission means is capable of driving the compression mechanism while varying the speed in a stepwise manner.

Since the structure of the conventional compressor with a transmission is complicated, the manufacturing costs are increased, and vibration noise is significant.

SUMMARY OF THE INVENTION

Accordingly, it is an objective of the present invention to provide a compressor with a transmission that has reduced manufacturing costs and noise.

To achieve the foregoing objective and in accordance with one aspect of the present invention, a compressor with a transmission is provided that includes a housing, a compression mechanism formed in the housing and being capable of compressing refrigerant, an input shaft extending into the housing from the outside of the housing, an output shaft extending in the housing, a transmission mechanism located between the input shaft and the output shaft in the housing, and a control mechanism for controlling the transmission mechanism. The input shaft is supported to be rotational about an axis. The output shaft is supported to be rotational about the axis and is capable of driving the compression mechanism. The transmission mechanism is capable of driving the compression mechanism at two different speeds by transmitting torque of the input shaft to the output shaft and also transmitting the rotational speed of the input shaft to the output shaft at an equal speed or an increased speed. The transmission mechanism includes a planet roller mechanism having a sun roller, a plurality of planet rollers, a carrier, and a ring roller. The carrier rotationally retains the planet rollers and is rotational integrally with the input shaft. The sun roller engages with the planet rollers and is rotational integrally with the input shaft.

The ring roller engages with the planet rollers and is secured to the housing by moving relative to the housing in a first direction parallel to the axis. The ring roller is rotational with respect to the housing by moving relative to the housing in a second direction, which is opposite to the first direction. The control mechanism includes a one-way clutch arranged between the carrier and the ring roller and a clutch arranged between the housing and the ring roller. The one-way clutch permits relative rotation of the carrier and the ring roller in one direction and restricts relative rotation in the other direction. The clutch selectively restricts and permits rotation of the ring roller by engagement between the housing and the ring roller. The clutch includes a friction layer arranged between the housing and the ring roller, a first control chamber formed in the housing and open toward the ring roller, a first control piston accommodated in the first control chamber and movable in the direction of the axis, a first thrust bearing arranged between the first control piston and the ring roller, a second control chamber formed in the housing, a second control piston accommodated in the second control chamber and movable in the direction of the axis, a second thrust bearing arranged between the second control piston and the ring roller, and a pressure control mechanism for controlling a first control pressure supplied to the first control chamber and a second control pressure supplied to the second control chamber. The friction layer secures the ring roller to the housing by movement of the ring roller in the first direction. The second control chamber faces the first control chamber and opens toward the ring roller.

Other aspects and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:

FIG. 1 is a longitudinal cross-sectional view illustrating a compressor with a transmission according to one embodiment of the present invention;

FIG. 2 is an enlarged longitudinal cross-sectional view illustrating part of the compressor with a transmission of FIG. 1 in a state where the clutch permits rotation of the ring roller; and

FIG. 3 is an enlarged longitudinal cross-sectional view illustrating part of the compressor with a transmission of FIG. 1 in a state where the clutch restricts rotation of the ring roller.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A compressor with a transmission according to one embodiment of the present invention will now be described with reference to the drawings.

Embodiment

As shown in FIG. 1, a compressor with a transmission (hereinafter, simply referred to as a compressor) includes a scroll type compression mechanism 20 to which a transmission mechanism 30 and a control mechanism 40 are integrally combined. The compressor is mounted on, for example, a vehicle and forms a part of an air conditioning system. In FIGS. 1 to 3, the left side, that is, the position at which an input shaft 1 is located is defined as the front side, and the right side, that is, the position at which an output shaft 2 is located is defined as the rear side.

The compressor includes a housing 10, which is formed by integrally fastening a first housing member 3, a second housing member 4, a third housing member 5, and a fourth housing member 6 in that order. The rear end face of the first housing member 3 and the front end face of the second housing member 4 engage with and are fastened to each other to form a transmission chamber 10 a. The transmission chamber 10 a is filled with traction oil. A passage 3 a is formed in the first housing member 3. The passage 3 a introduces the traction oil provided in an outer circumferential area of the transmission chamber 10 a to an inner circumferential area of the transmission chamber 10 a.

A fixed scroll 21 described below is integrally formed with the third housing member 5. Components such as a movable scroll 22 described below are accommodated between the second housing member 4 and the third housing member 5. The third housing member 5 and the fourth housing member 6 are fastened to each other so that a suction chamber 28 and a discharge chamber 29 are formed inside.

The input shaft 1 is supported by a boss of the first housing member 3 via a sealing member 7 and a bearing system 8 to be rotational about an axis O1. An assembly S includes the input shaft 1, a carrier 9, a radial bearing 31, planet rollers 32, a sun roller 14, a ring roller 33, a friction layer 35, a retaining ring 34 a, and a one-way clutch 34. The bearing system 8 is press-fitted in the first housing member 3, but a gap is formed between the bearing system 8 and the input shaft 1. The gap and a key 15 permit the assembly S to move with respect to the first housing member 3 in a direction parallel to the axis O1, that is, left or right in FIGS. 1 to 3. The forward or frontward direction corresponds to the first direction (fixing direction) of the present invention, and the rear direction corresponds to the second direction (releasing direction) of the present invention.

The rear end of the input shaft 1 protrudes in the rearward direction in the transmission chamber 10 a. A carrier main body 9 a is formed integrally with the input shaft 1 at the rear end of the input shaft 1. The carrier main body 9 a faces the first housing member 3 with a gap in between, and extends radially outward into a disk-like shape. The carrier main body 9 a forms a part of the transmission mechanism 30, which will be described below.

The output shaft 2 is supported in a boss of the second housing member 4 to be rotational about the axis O1 via a sealing member 11 and a radial bearing 12. The front end of the output shaft 2 is located in the carrier main body 9 a of the input shaft 1. A radial bearing 13 is also provided between the carrier main body 9 a and the output shaft 2. A passage 1 a is formed in the input shaft 1. The passage 1 a communicates with the passage 3 a formed in the first housing member 3 and extends to the radial bearing 13. The sun roller 14 located to the rear of the carrier main body 9 a is provided on the output shaft 2. The key 15 is provided between the output shaft 2 and the sun roller 14. The key 15 permits the sun roller 14 to rotate integrally with the output shaft 2 and to move with respect to the output shaft 2 in a direction parallel to the axis O1. The sun roller 14 also forms a part of the transmission mechanism 30 described below. The rear end of the output shaft 2 extends in the rearward direction toward the movable scroll 22.

The compression mechanism 20 will now be described. A drive bushing 23 integrated with a balancer and the movable scroll 22 are accommodated between the second housing member 4 and the third housing member 5.

The drive bushing 23 is secured to the rear end of the output shaft 2 in an eccentric state, and rotates integrally with the output shaft 2. A radial bearing 24 is arranged on the outer circumferential surface of the drive bushing 23.

The movable scroll 22 includes a boss 22 a, which is supported to be rotational with respect to the drive bushing 23 via the radial bearing 24, a disk-like movable plate 22 b, which is integrally formed with the boss 22 a and extends in the radial direction, and a movable volute portion 22 c, which protrudes in the rearward direction from the movable plate 22 b in parallel to the axis O1.

Three or more securing pins 25 a are secured to the rear surface of the second housing member 4 in parallel to the axis O1. Also, movable pins 25 b the number of which is equal to the number of the securing pins 25 a are secured to the movable plate 22 b of the movable scroll 22 in parallel to the axis O1. Furthermore, movable rings 25 c the number of which is equal to the number of the securing pins 25 a and the movable pins 25 b are arranged between the second housing member 4 and the movable plate 22 b. Each movable ring 25 c has a through hole 25 d. A pair of the securing pin 25 a and the movable pin 25 b are accommodated in the through hole 25 d in a state where the distance between the axes corresponds to the orbit distance of the movable scroll 22. The securing pins 25 a, the movable pins 25 b, and the movable rings 25 c form an anti-rotation mechanism 25, which prevents rotation of the movable scroll 22.

The fixed scroll 21 is formed integrally with the third housing member 5. The fixed scroll 21 includes a disk-like fixed plate 21 b, which extends in a radial direction, and a fixed volute portion 21 c, which protrudes in the forward direction from the fixed plate 21 b in parallel to the axis O1.

The protruding length of the fixed volute portion 21 c of the fixed scroll 21 and the protruding length of the movable volute portion 22 c of the movable scroll 22 in the direction of the axis O1 are set equal to each other. The fixed volute portion 21 c of the fixed scroll 21 slides with respect to the movable plate 22 b of the movable scroll 22, and the movable volute portion 22 c of the movable scroll 22 slides with respect to the fixed plate 21 b of the fixed scroll 21.

A discharge port 29 a extends through the central portion of the fixed plate 21 b to communicate with the discharge chamber 29. A discharge valve 26 and a retainer 27 are secured to the fixed plate 21 b in the discharge chamber 29 to close the discharge port 29 a. Furthermore, an intake port 28 a extends through the outer circumferential portion of the fixed plate 21 b. The intake port 28 a communicates with the suction chamber 28.

The second to fourth housing members 4, 5, 6, the output shaft 2, the drive bushing 23, the movable scroll 22, the anti-rotation mechanism 25, and the fixed scroll 21 form the scroll-type compression mechanism 20.

The discharge chamber 29 is connected to a condenser 42 via a pipe 41. The condenser 42 is connected to an evaporator 45 via an expansion valve 44 through a pipe 43. The evaporator 45 is connected to the suction chamber 28 via a pipe 46. A discharge pressure supply channel (the path Pd-Pd shown in FIG. 1), which supplies discharge pressure Pd in the discharge chamber 29 to a passage switching electromagnetic valve 63 described below, is provided in the discharge chamber 29. Also, a suction pressure supply channel (the path Ps-Ps in FIG. 1), which supplies suction pressure Ps in the suction chamber 28 to the passage switching electromagnetic valve 63, is provided in the suction chamber 28.

The transmission chamber 10 a communicates with the atmosphere via the passage 3 a and a filter 3 d. Also, the transmission chamber 10 a is partitioned from the compression mechanism 20, the suction chamber 28, and the discharge chamber 29 by the sealing member 11. Thus, the transmission chamber 10 a is filled with atmospheric pressure isolated from refrigerant.

The transmission mechanism 30 will now be described. As shown in FIGS. 2 and 3 in the enlarged state, four first support shafts 9 b and four second support shafts 9 c are provided in the transmission chamber 10 a. The first support shafts 9 b and the second support shafts 9 c protrude in the rearward direction and are alternately arranged along an imaginary circle defined about the axis O1 on the periphery of the rear surface of the carrier main body 9 a. One of the first support shafts 9 b and one of the second support shafts 9 c are shown in FIGS. 2 and 3. The first support shafts 9 b are columnar shafts, and the second support shafts 9 c are stepped columnar shafts having a large diameter portion at the middle. Each of the first support shafts 9 b rotationally supports the corresponding planet roller 32 via the associated radial bearing 31. The outer circumferential surfaces of the four planet rollers 32 engage the outer circumferential surface of the sun roller 14. The outer circumferential surfaces of the planet rollers 32 and the outer circumferential surface of the sun roller 14 have small surface roughness to prevent relative slipping.

One rear carrier 9 d is secured to the rear ends of the first support shafts 9 b and the second support shafts 9 c. The rear carrier 9 d has a substantially cylindrical shape extending in the rearward direction. An inner flange 9 e, which selectively contacts the rear end of the sun roller 14, is formed on the inner side of the rear carrier 9 d. The carrier main body 9 a, the first support shafts 9 b, the second support shafts 9 c, and the rear carrier 9 d form the carrier 9, which rotationally supports the four planet rollers 32 and rotates integrally with the input shaft 1.

The ring roller 33 is arranged between the planet rollers 32 and the first and second housing members 3, 4. The ring roller 33 includes a cylindrical first ring portion 331 and a cylindrical second ring portion 332. The first ring portion 331 and the second ring portion 332 are coupled to each other by pins 333.

The first ring portion 331 is formed of material having a relatively low rigidity, and can be displaced in the radial direction. The inner circumferential surface of the first ring portion 331 engages the outer circumferential surfaces of the planet rollers 32. Thus, the first ring portion 331 can be displaced in the radial direction using the interferences between the sun roller 14 and the planet rollers 32 and between the planet rollers 32 and the ring roller 33. The inner circumferential surface of the first ring portion 331 also has a small surface roughness to prevent relative slipping.

The second ring portion 332 is formed of material having a relatively high rigidity. The outer circumferential surface of the one-way clutch 34 contacts the inner circumferential surface of the second ring portion 332.

An inner flange 33 a, which selectively engages with the front ends of the planet rollers 32, is formed on the inner side of the first ring portion 331. An inner flange 33 b, which selectively engages with the rear ends of the planet rollers 32, is formed at the front end of the second ring portion 332. That is, the position of the planet rollers 32 and the ring roller 33 in the front and rear direction is determined by sandwiching the planet rollers 32 from the front and rear sides by the inner flanges 33 a, 33 b.

In the case where the first ring portion 331 and the second ring portion 332 are both rotational and move in the direction parallel to the axis O1, the second ring portion 332 supports the one-way clutch 34 maintaining high accuracy of, for example, the dimension and the cylindricity without being influenced by radial displacement of the first ring portion 331. Therefore, function of the one-way clutch 34 is not impaired.

The sun roller 14, the planet rollers 32, the ring roller 33, and the carrier 9 form a planet roller mechanism, which is the transmission mechanism 30 in this embodiment.

The one-way clutch 34 is secured to the outer circumferential surface of the rear carrier 9 d by the retaining ring 34 a. The outer circumferential surface of the one-way clutch 34 contacts the inner circumferential surface of the second ring portion 332 of the ring roller 33. The one-way clutch 34 is a known general-purpose component, and permits the ring roller 33 to rotate relative to the carrier 9 in one direction and restricts relative rotation in the other direction. In the present embodiment, the direction in which the input shaft 1 and the carrier 9 rotate about the axis O1 is set to the clockwise direction as viewed from the front of the compressor. While the one-way clutch 34 permits the ring roller 33 to rotate relative to the carrier 9 in the counterclockwise direction, the one-way clutch 34 restricts the ring roller 33 to rotate relative to the carrier 9 in the clockwise direction.

The friction layer 35, which faces the rear surface of the first housing member 3, is provided on the front surface of the first ring portion 331 of the ring roller 33. The friction layer 35 is an annular flat plate formed of material having a relatively high coefficient of friction. As will be described below with reference to FIG. 3, when the ring roller 33 moves in the forward direction, the friction layer 35 contacts the rear surface of the first housing member 3.

A first control chamber 136 is formed in the second housing member 4 at a position facing the rear surface of the ring roller 33 in such a manner as to form a recess. The first control chamber 136 is an annular groove coaxial with the axis O1, and is open toward the rear surface of the ring roller 33.

An annular first control piston 137 coaxial with the axis O1 is accommodated in the first control chamber 136. The first control piston 137 can move in the forward direction from the first control chamber 136. Ring grooves are respectively formed in the inner circumferential surface and the outer circumferential surface of the first control piston 137. Rubber O-rings 138 a, 138 b are fitted to the ring grooves.

That is, the first control piston 137 has the O-rings 138 a, 138 b arranged between the first control piston 137 and the first control chamber 136. The O-rings 138 a, 138 b seal the boundary between the first control piston 137 and the first control chamber 136.

A first thrust bearing 139 is mounted on the front portion of the first control piston 137. The first thrust bearing 139 faces the rear surface of the ring roller 33.

A second control chamber 236 is formed in the first housing member 3 in such a manner as to form a recess at the position facing the area outward of the friction layer 35 on the front surface of the ring roller 33. The second control chamber 236 is an annular groove that is coaxial with the axis O1, and is open toward the front surface of the ring roller 33. The first control chamber 136 and the second control chamber 236 face each other in the front and rear direction.

An annular second control piston 237, which is coaxial with the axis O1, is accommodated in the second control chamber 236. The second control piston 237 can move in the rearward direction from the second control chamber 236. Ring grooves are respectively formed in the inner circumferential surface and the outer circumferential surface of the second control piston 237. Rubber O-rings 238 a, 238 b are fitted in the ring grooves. That is, the second control piston 237 has the O-rings 238 a, 238 b arranged between the second control piston 237 and the second control chamber 236. The O-rings 238 a, 238 b seal the boundary between the second control piston 237 and the second control chamber 236.

A second thrust bearing 239 is mounted on the rear portion of the second control piston 237. The second thrust bearing 239 faces the front surface of the ring roller 33.

The outer diameter of the second control piston 237 is set to be greater than the outer diameter of the first control piston 137. Also, the distance between the inner circumferential surface and the outer circumferential surface of the second control piston 237 is set to be greater than the distance between the inner circumferential surface and the outer circumferential surface of the first control piston 137. Accordingly, a second control pressure receiving area of the second control piston 237 is set to be greater than a first control pressure receiving area of the first control piston 137.

A first control pressure supply passage 61, which connects the first control chamber 136 to the passage switching electromagnetic valve 63, is formed in the second housing member 4. The passage switching electromagnetic valve 63 selectively connects the first control chamber 136 to the discharge pressure supply channel (the path Pd-Pd shown in FIG. 1) and the suction pressure supply channel (the path Ps-Ps shown in FIG. 1). Thus, the first control pressure supplied to the first control chamber 136 is either the discharge pressure Pd or the suction pressure Ps.

A second control pressure supply passage 62, which connects the second control chamber 236 to the suction chamber 28, is formed in the first housing member 3 and the second housing member 4. Thus, the second control pressure supplied to the second control chamber 236 is always the suction pressure Ps.

As described above, the pressure in the transmission chamber 10 a against which the first control piston 137 and the second control piston 237 face is maintained at the atmospheric pressure. When the compressor is operated, the relationship between the discharge pressure Pd, the suction pressure Ps, and the atmospheric pressure is as follows.

Discharge Pressure Pd>Suction Pressure Ps>Atmospheric Pressure

A force F2, which presses the second control piston 237 in the rearward direction, is always applied to the second control piston 237 by the difference between the second control pressure in the second control chamber 236, which is the suction pressure Ps (>atmospheric pressure) in this embodiment, and the atmospheric pressure in the transmission chamber 10 a.

Force that presses the first control piston 137 in the forward direction applied to the first control piston 137 is changed as follows by switching the passage switching electromagnetic valve 63.

As shown in FIG. 2, when the passage switching electromagnetic valve 63 switches the first control pressure in the first control chamber 136 to the suction pressure Ps, a force Fs1, which presses the first control piston 137 in the forward direction, acts on the first control piston 137 by the difference between the suction pressure Ps in the first control chamber 136 (>atmospheric pressure) and the atmospheric pressure in the transmission chamber 10 a. In this case, the second control pressure receiving area of the second control piston 237 is set greater than the first control pressure receiving area of the first control piston 137. Thus, even if the first control pressure and the second control pressure are both the suction pressure Ps, the force F2, which presses the second control piston 237 in the rearward direction, is greater than the force Fs1, which presses the first control piston 137 in the forward direction.

In contrast, as shown in FIG. 3, when the passage switching electromagnetic valve 63 switches the first control pressure in the first control chamber 136 to the discharge pressure Pd, a force Fd1 (>Fs1), which presses the first control piston 137 in the forward direction, is applied to the first control piston 137 due to the pressure difference between the discharge pressure Pd in the first control chamber 136 (>suction pressure Ps>atmospheric pressure) and the atmospheric pressure in the transmission chamber 10 a. In this case, since the discharge pressure Pd is significantly higher than the suction pressure Ps, the force Fd1, which presses the first control piston 137 in the forward direction, is significantly greater than the force F2, which presses the second control piston 237 in the rearward direction.

The first control pressure supply passage 61, the second control pressure supply passage 62, and the passage switching electromagnetic valve 63 form a pressure control mechanism.

The friction layer 35, the first control chamber 136, the first control piston 137, the first thrust bearing 139, the second control chamber 236, the second control piston 237, the second thrust bearing 239, the first control pressure supply passage 61, the second control pressure supply passage 62, and the passage switching electromagnetic valve 63 form a clutch 60, which secure or rotate the ring roller 33 with respect to the first housing member 3. The one-way clutch 34 and the clutch 60 form the control mechanism 40.

An electromagnetic clutch 50 is coupled to the front end of the input shaft 1. The electromagnetic clutch 50 includes a disk-like hub 51, which is secured to the front end of the input shaft 1 to rotate integrally with the input shaft 1, an armature 53, which is connected to the hub 51 by a plate spring 52, and a coil 54, which is secured to the front surface of the first housing member 3. A pulley 56 is rotationally supported by the boss of the first housing member 3 via a radial bearing 55. A non-illustrated belt connected to an external driving source, which is an engine in this embodiment, is wound about the pulley 56. The coil 54 is arranged in the pulley 56.

In the compressor of the present embodiment formed as described above, when power is supplied to the coil 54 of the electromagnetic clutch 50, the armature 53 adheres to the pulley 56 by magnetic force against elasticity of the plate spring 52, as shown in FIG. 1. Accordingly, the input shaft 1 rotates integrally with the pulley 56, and torque is applied to the input shaft 1. When the input shaft 1 rotates about the axis O1, rotation of the input shaft 1 is transmitted to the output shaft 2 by the transmission mechanism 30 at an equal speed or an increased speed.

In contrast, when power supply to the coil 54 is stopped, although not shown, the armature 53 separates from the pulley 56 by elasticity of the plate spring 52, and torque applied to the input shaft 1 is disconnected. Thus, drive power applied to the input shaft 1 from the outside is disconnected by the electromagnetic clutch 50.

As shown in FIG. 1, in the compression mechanism 20, when the output shaft 2 is rotated, the drive bushing 23 rotates decentered from its axis, and the movable scroll 22 orbits in a state where rotation is restricted by the anti-rotation mechanism 25. Thus, the capacity of the compression chamber formed between the fixed scroll 21 and the movable scroll 22 decreases from the periphery toward the central portion. Thus, the refrigerant in the suction chamber 28 is compressed in the compression chamber, and discharged to the discharge chamber 29. The refrigerant in the discharge chamber 29 is supplied to the condenser 42, and vehicle is cooled by the evaporator 45.

Meanwhile, as shown in FIG. 3, when the passage switching electromagnetic valve 63 switches the first control pressure in the first control chamber 136 to the discharge pressure Pd, the force Fd1, which presses the first control piston 137 in the forward direction, becomes significantly greater than the force F2, which presses the second control piston 237 in the rearward direction as described above. Thus, the first control piston 137 moves in the forward direction against the force F2, which presses the second control piston 237 in the rearward direction. The first control piston 137 then moves the second ring portion 332 in the forward direction, the second ring portion 332 moves the first ring portion 331 in the forward direction, and the first ring portion 331 is pressed against the first housing member 3. Thus, the first control piston 137 presses the assembly S in the forward direction via the ring roller 33. Since the frictional force acts between the friction layer 35 and the first housing member 3, the ring roller 33 is secured to the first housing member 3.

Then, the one-way clutch 34 permits the ring roller 33 to rotate relative to the carrier 9 in one direction, or permits the ring roller 33 to rotate relative to the carrier 9 in the counterclockwise direction as viewed from the front of the compressor. Thus, the planet rollers 32, which orbit about the axis O1 in the clockwise direction in accordance with the rotation of the input shaft 1 and the carrier 9, rotate about the support shafts 9 b in the counterclockwise direction by the interference between the planet rollers 32 and the first ring portion 331. As a result, the sun roller 14, which contacts the planet rollers 32, and the output shaft 2, which rotates integrally with the sun roller 14, are rotated at the increased speed since rotation of the input shaft 1 is increased and transmitted.

In contrast, as shown in FIG. 2, when the passage switching electromagnetic valve 63 switches the first control pressure in the first control chamber 136 to the suction pressure Ps, the force F2, which presses the second control piston 237 in the rearward direction, becomes greater than the force Fs1, which presses the first control piston 137 in the forward direction as described above. Accordingly, the second control piston 237 presses the ring roller 33 in the rearward direction against the force Fs1, which presses the first control piston 137 in the forward direction. Thus, the friction layer 35 and the first housing member 3 are separated so that frictional force does not act between the friction layer 35 and the first housing member 3. This permits the ring roller 33 to rotate relative to the first housing member 3.

At this time, the entire assembly S moves in the rearward direction together with the ring roller 33. The first control piston 137 also moves in the rearward direction into the first control chamber 136 by being pressed by the ring roller 33 moving in the rearward direction.

Thus, the ring roller 33 starts to rotate clockwise about the axis O1 following the rotation of the input shaft 1. As the planet rollers 32, which engage with the sun roller 14, rotate clockwise, the ring roller 33 tends to relatively pass the input shaft 1 in the clockwise direction. The one-way clutch 34 restricts the ring roller 33 from rotating relative to the carrier 9 in the clockwise direction, that is, as viewed from the front of the compressor. In this state, the first thrust bearing 139 arranged between the ring roller 33 and the first control piston 137 rolls to prevent the ring roller 33 from dragging against the first control piston 137. The second thrust bearing 239 arranged between the ring roller 33 and the second control piston 237 also rolls to prevent the ring roller 33 from dragging against the second control piston 237. As a result, the input shaft 1, the carrier 9, the planet rollers 32, the sun roller 14, the ring roller 33, and the output shaft 2 rotate integrally. The output shaft 2 is rotated at the equal speed since the rotation of the input shaft 1 is transmitted at the equal speed.

Since the compressor employs the transmission mechanism 30 including the planet roller mechanism, vibration is not easily generated and noise is reduced. Also, the manufacturing costs are reduced since the compressor has a simple structure while the compression mechanism 20 can be operated at two different speeds.

Thus, the compressor of the present embodiment has less manufacturing costs and less noise. Also, the transmission chamber 10 a of this compressor is filled with the atmospheric pressure. Thus, when the first control pressure in the first control chamber 136 is switched to the suction pressure Ps, the first control piston 137 might not be retracted into the first control chamber 136 depending on the difference between the first control pressure in the first control chamber 136 and the atmospheric pressure in the transmission chamber 10 a. However, according to this compressor, the clutch 60 has the second control chamber 236 and the second control piston 237. Since the second control piston 237 moves in the rearward direction from the second control chamber 236, the ring roller 33 and the first control piston 137 is reliably moved in the rearward direction. Thus, the friction layer 35 and the first housing member 3 are reliably separated from each other, and friction between the friction layer 35 and the first housing member 3 is reliably eliminated. Thus, the ring roller 33 is reliably prevented from dragging. As a result, the compressor is not likely to cause power loss, and excellent compression efficiency is exerted.

Furthermore, according to the compressor, since the interior of the transmission chamber 10 a is isolated from the refrigerant, the transmission mechanism is further reliably operated by providing the interference between the sun roller and the planet rollers and between the planet rollers and the ring roller, and providing traction oil with high viscosity between them. Also, since the traction oil is reliably prevented from being mixed with the refrigerant, deterioration of the traction oil is prevented.

According to the compressor, the pressure control mechanism, which is the first control pressure supply passage 61, the second control pressure supply passage 62, and the passage switching electromagnetic valve 63 in this embodiment, reliably moves the first control piston 137 and the second control piston 237 in forward or rearward directions using the atmospheric pressure, the suction pressure Ps, and the discharge pressure Pd without separately providing a pressure supply source. Thus, the manufacturing costs are reliably reduced in to this compressor.

Furthermore, since the first control piston 137 and the second control piston 237 formed as described above press the ring roller 33 in forward or rearward directions uniformly about the axis O1, the transmission mechanism 30 is further reliably operated.

The present invention is described according to the embodiment but is not restricted to the illustrated embodiment. The invention may be embodied in the following forms without departing from the spirit or scope of the invention.

For example, in the present embodiment, the bearing system 8 is press-fitted in the first housing member 3, and a gap is formed between the bearing system 8 and the input shaft 1. However, a gap may be provided between the first housing member 3 and the bearing system 8, and the bearing system 8 may be press-fitted to the input shaft 1.

Also, in the present embodiment, the front direction is referred to as the first direction (fixing direction), and the rear direction is referred to as the second direction (releasing direction), but the front direction may be referred to as the second direction (releasing direction), and the rear direction may be referred to as the first direction (fixing direction). More specifically, the friction layer 35 may be provided at the rear end of the ring roller 33 instead of the front end of the ring roller 33. In this case, when the ring roller 33 moves in the rearward direction, the friction layer 35 is pressed against the second housing member 4.

Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalence of the appended claims. 

1. A compressor with a transmission, comprising: a housing; a compression mechanism formed in the housing and being capable of compressing refrigerant; an input shaft extending into the housing from the outside of the housing, the input shaft being supported to be rotational about an axis; an output shaft extending in the housing, the output shaft being supported to be rotational about the axis and being capable of driving the compression mechanism; a transmission mechanism located between the input shaft and the output shaft in the housing, the transmission mechanism being capable of driving the compression mechanism at two different speeds by transmitting torque of the input shaft to the output shaft and also transmitting the rotational speed of the input shaft to the output shaft at an equal speed or an increased speed; and a control mechanism for controlling the transmission mechanism, wherein the transmission mechanism includes a planet roller mechanism having a sun roller, a plurality of planet rollers, a carrier, and a ring roller, the carrier rotationally retains the planet rollers and is rotational integrally with the input shaft, the sun roller engages with the planet rollers and is rotational integrally with the input shaft, and the ring roller engages with the planet rollers and is secured to the housing by moving relative to the housing in a first direction parallel to the axis, and the ring roller is rotational with respect to the housing by moving relative to the housing in a second direction, which is opposite to the first direction, wherein the control mechanism includes: a one-way clutch arranged between the carrier and the ring roller, wherein the one-way clutch permits relative rotation of the carrier and the ring roller in one direction and restricts relative rotation in the other direction; and a clutch arranged between the housing and the ring roller, the clutch selectively restricting and permitting rotation of the ring roller by engagement between the housing and the ring roller, wherein the clutch includes: a friction layer arranged between the housing and the ring roller, the friction layer securing the ring roller to the housing by movement of the ring roller in the first direction; a first control chamber formed in the housing and open toward the ring roller; a first control piston accommodated in the first control chamber and movable in the direction of the axis; a first thrust bearing arranged between the first control piston and the ring roller; a second control chamber formed in the housing, the second control chamber facing the first control chamber and open toward the ring roller; a second control piston accommodated in the second control chamber and movable in the direction of the axis; a second thrust bearing arranged between the second control piston and the ring roller; and a pressure control mechanism for controlling a first control pressure supplied to the first control chamber and a second control pressure supplied to the second control chamber.
 2. The compressor with a transmission according to claim 1, wherein the housing includes a transmission chamber for accommodating the transmission mechanism, and a space in the transmission chamber is isolated from the refrigerant.
 3. The compressor with a transmission according to claim 2, wherein the first control piston has a first control pressure receiving area and the second control piston has a second control pressure receiving area, the second control pressure receiving area being set to be greater than the first control pressure receiving area, the first control pressure is one of a suction pressure of the refrigerant drawn into the compression mechanism and a discharge pressure generated by the compression mechanism, and the second control pressure is the suction pressure.
 4. The compressor with a transmission according to claim 1, wherein the first control piston and the second control piston each have an annular shape coaxial with the axis, the first control piston having an O-ring arranged between the first control piston and the first control chamber, and the second control piston having an O-ring arranged between the second control piston and the second control chamber. 